hypothetical question

I have perhaps a strange question that I have never had a straight answer on. I have donated blood over 10 times in Canada which uses the mha-tp test as it's screening test for syphilis. I haven't had sexual contact for 5 years before and during my donation time. I have never tested positive for syphilis.  My question is this, hypothetically, if you had untreated syphilis, is there any factors that contribute to always having a false negative result on the same mha-tp test repeated that many times? I've read that some times the treponemal antibodies fall below detectable levels. I've also read that 25% of the time in the latent stage the infection goes away on it's own and doesn't go in the late stage. Does that mean the infection is totally out of the body? Thank you for your time.

[H. Hunter Handsfield, M.D.]

Welcome to the STD forum.

You don't say where or from whom you have had difficulty getting a "straight answer" on this.  It's very straigtforward:  False negative tests are virtually unheard-of with MHA-TP and the other tests that measure antibody to Treponema pallidum, the bacteria that causes syphilis.  Once positive, such tests remain positive for life.  For a single person to have multiple false negative tests is essentially impossible.

Other kinds of syphilis blood tests, the "nontreponemal tests" like RPR and VDRL, often become negative over time, without treatment.  25% is about right.  The infection probably is totally eradicated by the immune system in some such persons, but sometimes the infection remains present in latent form.  But this does not occur with MHA-TP and related tests.

You can be 100% certain you do not have syphilis and never did.

Regards--  HHH, MD